In general, golf balls are provided with a multiplicity of dimples of circular plane shape on their surface for the purpose of improving their aerodynamic properties. It is well known that the dimpled golf balls are far better in flight behavior than smooth golf balls free of dimples.
The flight distance of golf balls depends on the initial velocity, drag and lift acting on the ball during flight, spin rate, and other factors such as weather conditions. It is considered difficult to make a theoretical analysis on golf balls with the aim of increasing their flight distance.
For improving the flight performance of the ball except for the initial velocity which is largely governed by the material of the ball, a number of attempts of tailoring dimples relating to the geometrical factors of the ball have been made. Such attempts include, for example, increasing the diameter of dimples, using plural types of dimples having different diameters, increasing or decreasing the depth of dimples, changing the shape of dimples from circular one to polygonal and other shapes, and increasing or decreasing the number of dimples. More or less fruitful results are obtained from these attempts.
There is still a demand to develop golf balls whose flight performance is satisfactory for the high skill level of professional and equivalent golfers.